1. Field of the Invention
The present invention relates to an improvement in a fixture for mixing hot and cold water from hot- and cold-water pipes so as to automatically regulate the temperature of mixed water discharged from a faucet.
2. Description of the Prior Art
The Japanese Laid-open patent publication No. 57-127171 discloses a known fixture of this type in which when a temperature sensing element senses a difference between the temperature of hot water and that of cold water, a valve is actuated thereby so as to control the temperature of hot water discharged from a faucet. FIG. 2 of this publication is included as FIGS. 9 and 10 in the accompanying drawings, in which a valve casing 50 includes a cold-water supply chamber 52, a hot-water supply chamber 51 which is partitioned from the cold-water supply chamber 52 by a partition wall 65, a mixed-water chamber 53, and an elongate tubular body 54 which is journalled within the mixed-water chamber 53. The left end of the elongate tubular body 54 constitutes a valve seat 56 through which cold water is admitted into the body 54 from the cold-water supply chamber 52. A blank cap 59 is screwed into a tapped hole 58 provided in the side wall of the hot-water supply chamber 51. The inner end of the blank cap 59 constitutes a valve seat 57. A hole 63 provided in the partition wall 65 serves as a valve guide for a stubby control valve 60 which is interposed between the valve seats 56 and 57. A casing 61 which accommodates a temperature sensing element 64 (FIG. 10 only) fits in the elongate tubular body 54. A hole 62 provided off-center in the left end wall of the casing 61 is in alignment with one of a plurality of holes 55 provided in the hub of the control valve 60 so that when the left annular surface of the control valve 60 is detached from the valve seat 57, hot water may be allowed to flow from the hot-water supply chamber 51 into the casing 61 so as to come in contact with the temperature sensing element 64.
This prior art fixture has a disadvantage that, during the passage of hot and cold water therethrough, the control valve 60 is apt to be pushed toward the low-pressure side. This is caused by the fact that there is a difference between the diameter D of the hole 63 and the diameter D.sub.1 of the circles formed by both ends of the control valve 60 on one hand, and by the fact that the control valve 60 is stubby on the other hand.
The above-described prior art fixture has another disadvantage in that the temperature sensing element 64 is not sensitive enough and it takes so much time for the control valve 60 to regulate the flow rate that a great loss of water is incurred. Such a low sensitivity is caused by the water current running slowly through an excessively large space T left between the internal surface of the casing 61 and the external surface of the temperature sensing element 64.
It is an object of the present invention to provide a fixture which eliminates the above-mentioned disadvantages.